1. Field of the Invention
The present invention relates to a buffer washer member used in a vibration and heat insulating board disposed, for example, around an exhaust manifold of an automotive engine, and a vibration and heat insulating board having the same.
2. Description of Background Art
As shown in FIG. 5, in an exhaust manifold 101 of an automotive engine 100, combustion emission of high temperature reaching several hundred degrees flows inside along with operation of the engine 100. To prevent heat and vibration generated in the exhaust manifold 101 from diffusing into the engine room or outside parts of the vehicle, a vibration and heat insulating board 102 is disposed around the exhaust manifold 101. If the vibration and heat insulating board 102 is directly coupled to the exhaust manifold 101 by means of bolts 103, heat and vibration of the exhaust manifold 101 are directly transmitted to the vibration and heat insulating board 102, and the effect of installation of the vibration and heat insulating board 102 is reduced. Accordingly, the exhaust manifold 101 and vibration and heat insulating board 102 are usually coupled by way of a buffer member not shown in the drawing.
Japanese Laid-open Utility Model No. S56-17313 discloses a heat insulating board which is prepared by disposing a wire mesh member in a mounting part on a vibration source, and coupling this wire mesh member integrally to a heat resistant metal plate. Japanese Laid-open Utility Model No. H4-71733 discloses a heat insulating board composed of inside and outside metal plates, and a heat resisting mesh interposed on substantially entire surface between these metal plates, in which the metal plates are notched around the mounting part of the heat insulating board to expose the mesh, and the exposed mesh is attached to a fixing member. In these heat insulating boards, vibration of the vibration source can be controlled, but it is not enough to shield the heat diffusion from the exhaust manifold, and mounting on the vibration source is unstable. To solve these problems, preparing two rigid members having flange members projecting from one end of sleeves horizontally to outside, the other ends of sleeves are joined to form a collar member, and a wire mesh member having a hole larger than the outside diameter of the sleeves but smaller than the outside diameter of the flange members is freely fitted in the sleeves to compose a heat insulating board. According to this heat insulating board, the collar member is firmly tightened by bolts to the specified fixing position of the vibration source, the collar member and wire mesh member are coupled in freely fitting state, and therefore the contact parts thereof are only partial and variable, so that the heat insulating effect is high.
(Patent reference 1) Japanese Laid-open Utility Model No. S56-17313 (claim 1)
(Patent reference 2) Japanese Laid-open Utility Model No. H4-71733 (claim 1)